The present invention relates to a controller for controlling the manufacturing of hot strip using a multi-stand hot-strip rolling mill, and, in particular, a wide-strip mill. A sampling plan including initial and final measurements, material data, rolling temperatures, etc. is provided. A control system for controlling the setpoint of lower-order coupled individual controllers for the variable functional parameters of the individual stands (e.g. roll adjustment, rotational speed, torque, etc.) is also provided. In the present invention the setpoints of the individual controllers are computed using model equations involving convergent parameter adjustment to the actual parameters such that setpoint control, that can be predetermined, is obtained.
In hot-strip rolling mills, producing a strip having a required section development and flatness by means of a small number of simple rolling mill stands, without requiring costly mechanical roll actuators is desired. If the need for roll actuators is unavoidable, these actuators should be simple and limited to only a few rolling mill stands. Particularly, in hot wide-strip mill trains designed according to these criteria, there was formerly no way to optimize the thickness section of the strip. A sampling plan design based on experiential values continues to be the norm.
The European Patent Application EP-0 121 148 B1 discusses a section and flatness control for hot-strip tandem mill trains in which the strip section at the critical thickness (below which no significant reshaping of the rolled strip can be achieved) is used as the basis of an expensive flatness and section development control of the hot strip. An equivalent control is disclosed in the German Patent Application DE-27 36 234 A2. Rolling mill trains with the above mentioned controls require a plurality of thickness, section, and flatness measuring devices along the mill train and expensive stand controls. As a result, the total cost of a hot strip whose production is controlled in this fashion is high. This is especially true when a wide strip rolling train is used. Further, both the measured values and the roll actuators are costly to maintain and significantly increase operating expenses.
The goal of the present invention is to provide a control for controlling the manufacturing of hot strip with a multiple-stand hot-strip rolling mill, and in particular, a wide-strip mill. The control of the present invention permits the mill to produce rolled strip within tolerance by employing model calculations, especially with the aid of automatically adaptable model calculations. Hence, the control of the present invention requires only a minimum of expense. In particular, old rolling mill trains can be modernized with the control according to the present invention without having to rebuild the rolling mill trains and without needing to provide the rolling mill trains with a plurality of expensive measuring devices and actuators on the roll stands.